.map {
  position: absolute;
  display: block;
  width: 660px;
  height: 660px;
  left: 50%;
  top: 50%;
  margin-top: 20px;
  margin-left: -330px;
}
.map-tr {
  position: relative;
  margin-left: auto;
  margin-right: auto;
  width: 100%;
  height: 20px;
}
.map-td {
  position: relative;
  float: left;
  width: 20px;
  height: 20px;
  border: 1px solid #ddd;
  box-sizing: border-box;
  background-color: white;
  margin: 1px;
  border-radius: 50%;
}
.selected {
  background-color: #ddd;
}
.food {
  background-color: green;
}
.snake-head {
  
}
.snake-img {
  border-radius: 50%;
}